Thermostat control system



Nov. 19, 1940. B, NEWTON THE'RMOSTAT CONTROL SYSTEM Filed Dec. 28, 1959 01,11" 'IIIIIIIIII.

'IIIIIIIIIIIIIlIIIIIIIIIIIIlII/Ifl 'II/IIIIIIIIIA 'IIII/IIIIIlIIIIIIIIlIIlII/lI/IIIII inventor Alwiru B. N'zwi-on...

ill

till

till

hit

illustrates .liliwin lilt l lewton, to lhlinneapoliahioneywc iiiirnncapolis lillinm, a corporation oi llic illlth "oils, llliirml, i tcmulator ilhwi application iiliecemiocr lihiill, herial lilo, tillhllhli this invention relates in general to automatic controls and more-particularly to thermostatic controls tor controlling air conditioning apparatus in hath summer and wiuter'.

The ohject of this invention is to provide a simple thermostatic or condition responsive control arrangement which operates to'increase the heating chest of air conditioning apparatus in winterupon tall in temperature and to increase the cooline-eiiect of such apparatus in summer upon rise in temperature.

linother ohiect oi this invention is to provide an automatic control arrangement arlapterl to control in one manner at one time and in the reverse manner at another time and to iurther provide an arrangement oi this type ior positively reversine the control from one manner to the other. I

h ther ohiects oi this invention will appear irom the lollow'ina description and the appended claims.

ll or a tall disclosure oi this invention reference is made to the iollowina description and to the accompanyina drawina, the single liaure at which diagrammatically a small summerwinter air conditioner and the thermostatic controts thereior. 1

liteierrlna to the urawina reierence character it inriicatea an ah eonrlitionina unit ariapteci to he located in a space heins conciltioneri. this unit may he located in any room or enclosure which it is desired to condition and is illustrated as one which is especially adapteti tor contiitionina compartments in a railway car. llhis unit is provirletl with a retuinair inlet ii tin-hash which air irom the space olrawn. also the unit is provided with a trash air inlet it which he connecterl to a suitahle iresh air rluct. "the contlitionina unit it also includes a heat enchanae coil t which is connecteti to smtahle source oi supply oi heatine or coolina mccliam. marina the heatina season this coil is supplied with heatina medium such as hot water and chains the coolina season this coil is suppllerl with coolina meuium such as cola water. it tan located within the conolitionina unit tor tirawlna air tin-ouch the inlets l and i over the call it and discharrgina it into the space throuah a suitahle still i.

"the how of air through the inlets i and l is controlled by means oi damper blades l and i, the hlades 'l controlling the flow of fresh air throaah the inlet l and the blades 8 controlling the how of return air through the inlet 2. These hiacies l and 8;. are connected to an operating which is out. arcn memher ll so that the hlarles rotate in umson anti in the same direction. it will he noted that the damper hlarles do not overlap which permits rotation at these hlarles in either direction from the closed position shown in the than when the operating memher is in the intermediate position shown, the damper lalaoles l and are in their closed positions wherein now at air across the coil i is snhstantially prevented. Upon upward movement oi the operation memher the W blades l and it will rotate counterclochwise thereby permitting how at air across coil [Flimilarly upon downward movement at the operating memher ii the hlarles l and will rotate closinwise which also permits how of across coil i.

The operatina memher is shown as heina actuaterl by means oil a hell cranlr memher iii, the memher ii heine secured to the hell cranlr it by a pin and slot connection 11 i. This hell cranlr iii is hiaseri in the cloclrwlse direction hy means at 2 a sprina ill, this servina to urge the hell cranlr iii a lever ill which is pivoted at it. the upper emi oi lever ill is formed as a near segment i enaaaina a similar seament it iormetl on lever ill which is pivoted at ll'hls wj lever is rotated ahout pivot hy means at a thermostatic hollows iii, this hollows-heme; connectcol hy a capillary tuhe to a hulh it located in the return air inlet l oi the conditioner. The hollows, tuhe anti halh are chara'etl with a suitahle l volatile till which causes the hollows to expand anti contract upon choose in return airtemperstate. "the lever iii maeri the hollows hy means at sprina lilo. sprint; may

he adjusted so that when the temperattu'e in the 3 till sprina it) which will cause counter-clocirwise ro M tation oi the hell cranlr. iii lor lowerina' the actuatina memher it which in turn causes rotation oi the damper hlaoies l and t cloclrwise tor permittine air flow across coil i. it will he apparent that the decree oi openina or hlades ll anal i will so he dependent upon the departure of the space temperature from the desired value. it the space temperature rises alcove the desired value the hollows M will expand against the action of spring l2 thereby forcing lover ii clockwise from the intermediate position illustrated. This will cause counter-clockwise rotation of the lever I3 for causing upward movement of the actuating member 9 which will rotate the damper blades I- and 8 counter-clockwise from the closed position. From the description thus far it will be apparent that whenever the space temperature is at the desired value the damper blades 1 and 8 will assume the closed positions shown, and that upon either rise in temperature above or fall in temperature below the desired value the damper blades will be opened in proportion to the departure in room temperature from a desired value.

During the. heating season when heating medium is supplied to the coil 4, it is necessary to prevent the dampers from being opened upon rise in temperature above the desired value. Also during the cooling season when coooling medium is supplied to the cooling coil it is necessary to prevent the dampers from opening upon fall in room temperature below the desired value. In order to prevent opening of the damper upon rise in temperature during the heating season or upon fall in temperature during the cooling season a lever 22 is provided having a slotted arm 23 I through which the lever I3 passes, this slotted arm providing stops 24 and 25. The lever 22 is actuated by means of a bellows 26 which is connected by a capillary tube 27 to a control bulb 28 mounted upon the heat exchange coil 4. The lever 22 is biased against the bellows 26 by means of a spring 29. This lever is also arranged to abut adjustable stop screws 30 and 3 I.

During the heating season, heating medium is supplied to the coil 4 at a temperature of 100 F. or higher. Due to the bulb 28 responding to the temperature of coil t, the vapor pressure of the volatile fill will be relatively high which causes the bellows 26 to expand for forcing the lever 22 into engagement with the stop screw 30. This causes the stop 25 to be brought into position for preventing counterclockwise rotation of the lever I3 from the intermediate position. Upon decrease in space temperature from the desired value the bellows It will contract which will cause counter-clockwise rotation of the lever Il about pivot I8. This will cause clockwise rotation of lever l3 about pivot I4, the lever I3 being free to move in this direction between stops 23 and 24. This clockwise rotation of lever I3 will cause counter-clockwise rotationof the bell crank l which lowers the actuating member 9 for rotating the blades I and t in clockwise direction from closed position. Thus upon fall in space temperature the dampers l and 8 will open for permitting air to flow acrossthe coil 4. It will be noted that if the space temperature rises above the setting of the actuating thermostat, the lever I3 will engage the stop 25 which prevents it from moving beyond intermediate position and'therefore a rise in temperature when heating medium is supplied to the coil cannot cause opening of the dampers I and 8.

When cooling medium is supplied to the coil 4 such medium will be at or below 50 F. which will cause the vapor pressure in bellows 26 to be relatively low, this permitting the spring 29 to hold lever 22 against the stop screw 3|. This position of the lever 22 will cause the stop 24 to be brought into engagement with the lever I3 when it is in its intermediate position. At this time upon rise in space temperature from the desired value, the bellows I9 will expand thereby rotating the lever I'I clockwise which in turn bellows rotates lever I3 counter-clockwise. The stop 25 will now be removed which permits the lever I3 to rotate freely in this direction thus permitting air to flow across the coil 4. However, if the space temperature falls below the setting of the thermostat, the thermostat will attempt to rotate the lever I3 clockwise. Such motion of lever I3 will be prevented due to its engagement with the stop 24. Thus a fall in temperature belowthe setting of the thermostat when the system is acting to cool will not result in opening of the dampers.

It will be noted that the changes in room temperature affecting the pressure in bellows I9 are quite small as compared to the difference in temperature of the heating and cooling medium supplied to the heat exchanger 4. In other words the room or return air thermostat operates through a difierential of only several degrees F. while the change-over thermostat responding to the heat exchanger temperature is subjected to changes in temperature of 50 F. or more. The change in pressure in the bellows 26 between the heating and cooling seasons is therefore very large as compared to changes in pressure in the I9 which renders the bellows I9 incapable of forcing the stops 24 or 25 away from the proper positions. While for convenience the invention has been described as applied to a system in which the temperature of the heat exchange fluid is shifted suddenly from hot to cold, the invention will operate equally well when applied to a system in which the temperature of the heat exchange fluid is graduatingly varied from hot to cold as the load changes from heating to cooling. This is due to the fact that the thermostat which adjusts the stops assumes mid position at the same temperature as the damper thermostat places the dampers in mid position. For example, when the room temperature is at 74, the dampers I and 8 are closed and when the heating medium temperature is at 74, the lever 22 which carries stops 24 and 25 will be in mid position thus rendering both stops substantially inefiective. However, at this time, no stops are necessary as the room temperature and heat exchanger temperature are equal which causes the damper position to have no affect upon room temperature. Now as the heat exchanger temperature varies from 74, the efiect of the damper position upon room temperature increases, but at this same time, the force available for holding the lever 22 against stop screw 30 or iii increases, so that the efiectiveness of the stop increases in proportion to the necessity for such effectiveness.

From the foregoing description it will be apparent that this invention provides a simple arrangement for automatically controlling an air conditioner in both summer and winter and which will not operate reversely at any time. While it is preferred to utilize the automatic changeover or stop mechanism illustrated, the invention is not limited to the automatic changeover mechanism as the stops may be adjusted manually if so desired. While the invention is particularly adaptable to direct control of small units as illustrated the invention is not limited to the self contained type control system illustrated and may be incorporated into thermostats or other year around controls which in turn control air conditioning motor devices. As many modifications may be made without departing from the scope of the invention it is desired to be till all

limited only hr the scope or the appended claims.

l. claim as my invention:

l. in an air conditioning system, in comhination, conditioning means for treating and cooling said space, a controller for controlling said conditioning means, said controller mid position wherein. hoth heating and cooling are prevented and operative to graduatinglv increase the effect of said conditioirnig means upon movement in either direction from position, a thermostatic element responsive to the temperature of said space for moving said controller in a first direction from mid position upon temperature and tor moving said controller in the opposite direction from mid position upon tall in temperature, first movahle stop means tor resisting movement of said controller in said ltlrst di rection from. mid position, second movahle stop means tor resisting movement at said controller in the opposite direction tram mid position, and means for rendering one or the other of said step means ineffective.

2. in an air conditioning svstem, in combination, conditioning means :for heating and cooling said space, a controller for controlling said conditioning means, said controller having a mid position wherein hoth heating and cooling are prevented and operative to graduatingiv increase the effect of said conditioning means upon movement in either direction from said mid position, a ther mostatic element responsive to the temperature of said space for moving said controller in a first direction from mid position upon rise in temperature and for moving said controller in the opposite direction from mid position upon tall in temperature, first movaiole stop means for resisting movement of said controller in said first direction from mid position, second movalole stop means for resisting movement of said controller in the opposite direction from mid position, a single actuator for actuating hoth ct said movable stop means, said actuator having a first position rendering said first stop means ineffective and said second stop means ettective and a secand position rendering said stop means effective and said second stop means ineffective.

ii. in an air conditionlr g svstem, n comhina tion, conditioning means heating and cooling said space, a controller tor controlling said conditioning means, said controller mid position. wherein, Tooth heatng and cooling prevented and operative to aduathiglr increase the effect oi said conditioning the upon merit in either direction tram said nrld position. a thermostatic element resr ronsive the tern-- perature of said space tor moving said controller in a first direction trom position upon in temperature and tor moving said controller in the opposite direction tron-i mid position upon tall in temperature, first movahle stop means tor resisting movement oi said controller in said first direction from mid position, second movahle stop means tor resisting movement of said controller in the opposite direction :from mid position, a

single actuator for actuating tooth of mar-- able stop means, said actuator having a hrst position rendering said first stop means lnedective and said second stop means edcctlve and a secend position rendering said first stop means ciifective and said second step means lneflective, and thermostatic means responsive to a temperature varying with the demand for heating or cooling for controlling said actuator.

t. in an air conditioning system, in combinadi t.

tion, conditioning means tor heating said space, a controller for controllin cooling conditioning means, said controller having midin a first direction trom position upon rise in temperature and tor moving said controller in the opposite direction trom mid position upon fall in temperature, first movahle stop meaml re" sisting movement oi said controller in said direction trom mid position, second movalole means tor resisting movement at s id controller in the opposite direction from portion, single actuator for actuating hoth oi mot ahle stop means, said actuator having po sition rendering said stop means inch ectlve and said second stop means effective and sec end position rendering said first stop means eiiec tive and said second stop means 'lneiiective, a pair of stops associated with said actuator for determining the first and second positions or said actuator and a pressure motor tor shitting said actuator between said pair of stops.

5. In an air conditioning system, in comhination, heat exchange means for heating or cooling a stream of air passing to a space, means for selectively supplying heating or cooling medium to said heat exchange means, damper means for controlling the now of air over said heat ea change means, said damper means having an in termediate position in which the air hou is reduced to a minimum and acting to increase the flow of air over said heat exchange means upon movement in either direction from said intermediate position, means including a thermostatic element responsive to the temperature in the space tor causing said damper means to assume said intermediate position when the space temperature is at a desired value, vvhile causing said damper means to move in one direction upon rise in temperature and to move in the opposite direction upon fall in temperature, a stop for preventing movement of said damper means in one direction from said intermediate position, a second stop for preventing movement oi said damper means in the opposite direction intermediate position, and means tor selcctivelv rendering one or the other oi said stops moltentive.

a stream at air passing to space, means tor selectively supplying heating or cooling mediumto said heat enchange means, damper means tor controlling the new of air over said heat errchange means, said damper means having an r intermediate position in which air dotv reduced to a minimum and acting to increase the tlotv oi air over said heat enchange means upon, movement in either direction irom said intermediate position, means including a thermostatic element responsive to the temperature in the space for causing said damper means to assume 6. in an air conditioning system, in comhlnation, heat exchange means for heating or cooling damper means in the opposite direction from said intermediate position, and thermostatic means responsive to a temperature varying with de-- mand for heating or cooling for rendering one of said stops ineffective upon demand for heating and for rendering the other of said stops ineffective upon demand for cooling.

7 7. In an air conditioning system, in combination, heat exchange means for heating or cooling a stream of air passing to a space, means for selectively supplying heating or cooling medium to said heat exchange means, damper means for controlling the flow of air over said heat exchange means, said damper means having an intermediate position in which the air flow is reduced to a minimum and acting to increase the flow of air over said heat exchange means upon movement in either direction from said intermediate position, means including a thermostatic element responsive to the temperature in the space for causing said damper means to assume said intermediate position when the space temperature is at a desired value, while causing said damper means to move in one direction upon rise in temperature and to move in the opposite direction upon fall in temperature, a first stop for preventing movement of said damper means in one direction from said intermediate position, a second stop for preventing movement of said damper means in the opposite direction from said intermediate position, and thermostatic means responsive to the temperature of the medium supplied to said heat exchange means for rendering one of said stops inefiective when heating medium is supplied to said heat exchange means and for rendering the other of said stops ineffective when cooling medium is supplied to said heat exchange means.

8. In an air conditioning system, in combination, heat exchange means for heating or cooling a stream of air passing to a space, means for selectively supplying a stream of cooling medium or heating medium to said heat exchange means, a flow: controller for controlling one of said streams, said flow controller having an intermediate position wherein the efiect of said heat exchange means is reduced to a minimum and acting to increase the effect of said heat exchange means upon movement in either direction from said intermediate position, a thermostatic element responsive to the temperature in said space, a mechanical linkage between said thermostatic element and said flow controller whereby said ilow controller is positioned by said thermostatic element, a first stop means for preventing movement of said flow controller by said thermostatic element in one direction from said intermediate position, a second stop means for preventing movement of said flow controller by said' thermostatic element in the opposite direction from said intermediate position, and selective means for rendering one or the other of said stop means inefiective.

9. In an air conditioning system, in combination, heat exchange means for heating or cooling a stream of air passing to a space, means for selectively supplying a stream of cooling medium or heating medium to said heat exchange means, a flow controller for controlling one of said streams, an actuating member for actuating said flow controller, said actuating member and flow controller being arranged in a manner to cause the effect of the heat exchange means to be reduced to a minimum when the actuating member is in an intermediate position while acting to increase the efiect of said heat exchange means upon movement of said actuating member in either direction from said intermediate position, a thermostatic element responsive to the temperature of said space, connecting means for transmitting movements oi said thermostatic element to said actuating member, a first stop means for preventing movement of said actuating member by said thermostatic element in one direction from said intermediate position, a second stop means for preventing movement of said actuating member by the thermostatic ele ment in the opposite direction from said intermediate position, and selective means for rendering one or the other of said stop means inefiective.

ALWIN B. NEWTON. 

